Refrigeration system



p 1965 E. w. SCOTT REFRIGERATION SYSTEM 2 Sheets-Sheet 1 Filed April 19 1963 Fig.l.

INVENTOR Eugene W. Scott BY QM M WITNESSES ATTORNEY Sept. 28, 1965 E. w. scoTT 3,208,235

REFRIGERATION SYSTEM Filed April 19, 1963 2 Sheets-Sheet 2:

United States This invention relates to refrigeration apparatus, and more particularly to a two temperature refrigerating system for use in a compartment type water cooler.

A recent improvement in water cooler apparatus is known as the compartment type water cooler. The compartment cooler generally combines a cooling compartment which provides for the freezing and storage of ice cubes together with water cooling and storage facilities. A more useful and versatile product is, therefore, offered by this arrangement.

In economically combining the water cooling function with the freezing of ice cubes, a single refrigeration system should be provided which maintains a below freezing temperature in the ice cube enclosure and does not permit the temperature of the water storage enclosure to fall below freezing.

It is, therefore, an object of the invention to provide a refrigeration system which is simple and easy to manufacture and suitable for use in a compartment water cooler.

Another object of the invention is to provide a multiple temperature refrigeration system having simple and effective means to prevent a temperature in the system from lowering after the compressor is shut down.

These and other objects which will become apparent as the description proceeds are achieved by providing a closed refrigerant circuit of the compressor-condenserevaporator type having a plurality of evaporators connected in series refrigerant flow. The temperature of each evaporator may be simply controlled by employing capillary restrictors between the evaporators in a manner well known in the art.

During operation of the compressor each of the evaporators maintains the proper temperature by evaporating a portion of the liquid refrigerant flowing therein.

However, when the compressor is shut down, the pressure in the system tends to equalize and the pressure in a high temperature evaporator will approach that of a lower temperature evaporator. The pressure change in the high temperature evaporator causes further expansion of any liquid refrigerant contained therein, with a resulting lowering of the temperature approaching that of the low temperature evaporator. In a compartment water cooler employing the system, the temperature of the water cooling evaporator would approach the temperature of the ice freezing evaporator which is undesirable.

In practicing the invention, a header or refrigerant accumulator means is provided in the system following the evaporator whose temperature is to be prevented from dropping.

When the system is shut down, and the compressor is inoperative, the liquid refrigerant remaining in the evaporator will be quickly discharged into the header by virtue of the free passageway without traps, the gas pressure in the condenser, and by gravity. Any further evaporation of liquid will take place in the header or in the evaporator following the header. Therefore, although the pressure of the higher temperature evaporator reaches a pressure corresponding to that of a colder evaporator in the system, the temperature of the higher temperature evaporator will not be appreciably lowered from the temperature reached at the time of compressor shut off, nor will appreciable refrigeration take place in the warm evaporatent ator because of the lack of liquid in this part of the system.

For a better understanding of the invention reference should be had to the accompanying drawings, wherein:

FIGURE 1 is a perspective view of a compartment type water cooler having the invention employed therein;

FIG. 2 is an enlarged elevational view of the water cooler of FIG. 1 showing schematically the elements of the refrigerating system;

FIG. 3 is an elevational view similar to FIG. 2, but showing the invention incorporated in a second embodiment of a compartment water cooler; and

FIG. 4 is a schematic diagram of the refrigeration system shown in FIGS. 2 and 3.

Although the principles of the invention are broadly applicable to refrigerating circuits in general, the invention has been herein illustrated as employed in a compartment water cooler and will be so described.

Referring to the drawings, especially FIG. 1, there is shown a compartment-type water cooler 10 having a customary fountain device 11 for dispensing cool drinking water. A cooling compartment 12 is located in the upper portion of the cooler 10 and has an enclosure 13 for the freezing of ice cubes.

Referring now to FIG. 2, a water chamber 14 is shown disposed in the cooler 10 providing an enclosure for the storage of drinking water to be cooled. Water is received in the chamber 14 from any suitable outside source and is dispensed by the fountain device 11 in the usual manner. As the piping and valve arrangements necessary to supply fresh water to the water cooler 10, and to drain waste water from the cooler may be of any suitable type known in the art, details thereof have not been shown, as they form no part of the present invention.

Both the water storage chamber 14 and the cooling compartment 12, including the enclosure 13, are maintained at the proper temperatures by the refrigerating system having components arranged as best shown in FIG. 2. Disposed adjacent the bottom of the cooler Ill is a compressor 16 connected to a refrigerant condenser 18. From the condenser 18 a capillary tube 19 extends to the evaporator coils 20 disposed adjacent the water storage chamber 14. The evaporator coils 20 embrace the walls of the tank 14 in a manner providing heat transfer from the Water contained in the chamber. A header, or refrigerant accumulator, 21 is shown in spaced relation below the evaporator coils 20 having an end 22 of the coils entering the upper portion of the header to provide inlet means to the header. A second capillary restrictor 23 extends into the header 21, having an end, or an extension thereof, 24 disposed adjacent the lower portion of the header thereby providing outlet means from the header.

The capillary tube 23 serves to connect the header 21 to a lower temperature evaporator 26, which herein is shown as a plate type, located in the compartment 12, and cooperating with the upper wall thereof to form the enclosure 13. A conduit 27 is connected to the outlet of the low temperature evaporator 26 and extends downwardly into the suction line accumulator 28. A second conduit 29 extends from the accumulator 28 and connects the accumulator to the compressor 16 to complete the refrigerating circuit.

Operation of the compressor 16 is controlled by a control switch 31 and the cooperating sensing element 32 which is disposed adjacent the evaporator coils 20. The control switch 31 may be of any type known in the art, and is preferably adjustable to provide shutting down the compressor 16 in response to various selected temperatures of the evaporator coils 20 or the liquid within the evaporator. A second control switch 33 is provided in the electrical circuit, and has a sensing element 34 extending into the compartment 12. Sensing element 34 and control switch 33 are of the usual commercial type and may have a fixed control point, when desirable for protection, at which the control switch acts on the circuit to terminate operation of the compressor unit.

A fan 36 is shown disposed adjacent the condenser 18 and is connected in the electric circuit of the compressor 16. The fan 36 operates during the compressor operating cycle and serves to dissipate heat from the unit by passing air over the condenser 18.

For an understanding of the operation of the invention, reference should be had to FIG. 4 wherein the elements of the refrigeration circuit are schematically shown removed from the cabinet. When the evaporator 21) reaches a temperature calling for a cooling cycle, operation of the compressor 16 is initiated, and liquid refrigerant is formed in the condenser 18. The liquid refrigerant is then metered through the capillary tube 19 to the evaporator 20 where a portion of the liquid refrigerant is evaporated. The mixture of liquid and gaseous refrigerant flows from the evaporator 20 into the header 21 through the inlet 22, from which it is metered through the capillary tube 23 into the evaporator 26. In the evaporator 26, the liquid refrigerant is further expanded to produce cooling and is then directed through the conduit 27 into the accumulator 28. In the accumulator 28, any liquid refrigerant remaining in the system is separated from, and eventually expanded to, a gas which returns through the conduit 29 to the compressor 16 to complete the cycle.

When the temperature of the evaporator 20, or the temperature of the compartment 12, calls for a termination of the refrigeration cycle, the compressor 16 will be shut down. At that time, the pressure in the evaporator 20 is greater than the pressure in the evaporator 26. Thus, with the compressor inoperative, the liquid refrigerant in evaporator 20 will have a tendency to evaporate and expand to the pressure maintained in the evaporator 26, causing further refrigerating effect in the evaporator 20. However, by locating the header 21 in the circuit, as shown, no significant evaporation of liquid takes place in the evaporator 20. When the compressor 16 is shut down, any liquid refrigerant contained in the evaporator 20 is quickly drained by refrigerant pressure supplemented by gravity flow into the header 21. With the compressor 16 inoperative, the pressures tend to equalize between the evaporator 26 and the evaporator 20. However, evaporation of liquid refrigerant caused by the pressure equalization takes place in the header 21 and produces no further cooling of the evaporator 20. Therefore, although the pressure in the evaporator 20 is now substantially equal to the pressure in the evaporator 26, the temperature of the evaporator 20 is substantially the same temperature as at the time of compressor shutdown.

In FIG. 3, there is shown a second embodiment having the invention employed in a compartment water cooler of the type employing bottled water. The Water cooler 40 has a compartment 42 having an enclosure 43 for freezing ice cubes. A water storage chamber 44 is provided adjacent the top of the cooler 4% to facilitate installation and removal of the bottle 45 containing drinking water. Elements of the refrigeration system employed in this embodiment are similar to the system shown in FIGS. 2 and 4, but for their location in the cabinet.

In this system, as in the prior embodiment, it will be noted that the header 21 is located in spaced relation below the evaporator 20, thereby providing gravity flow in addition to vapor pressure to cause quick drainage of the evaporator. It should be understood, however, that the invention is not limited to a system wherein the quick drainage of the evaporator 20 is aided by gravity flow. The pressure caused by the evaporation and expansion of the refrigerant in the high temperature evaporator 20 will, in many situations, be found suificient to cause a rapid flow of liquid refrigerant from the evapod rator without the aid of gravity, when the compressor 16 is shut down.

From the foregoing, it should be obvious that the invention provides a multiple temperature refrigeration system having a simple and effective means to prevent an evaporator temperature in the system from being lowered after the compressor is shut down. Further, the invention provides a system which is simple and easy to manufacture and is highly desirable for use in a compartment water cooler.

While the invention has been shown in but two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various additional changes and modifications without departing from the spirit thereof.

What is claimed is:

1. A mechanically refrigerated cabinet having an enclosure to be maintained at a low temperature,

an enclosure to be maintained at a higher temperature,

and

a closed refrigerating circuit including: liquifying means for supplying liquid refrigerant to said circuit,

a first evaporator disposed in heat transfer relation with said higher temperature enclosure,

a second evaporator disposed in heat transfer relation with said low temperature enclosure and in series refrigerant flow with said first evaporator,

restrictor means for controlling the flow of refrigerant to said second evaporator, and

means for draining liquid refrigerant from said first evaporator when said liquefying means is inoperative, said means including a header disposed between said first evaporator and said restrictor means, said header having sufficient volumetric capacity relative to said first evaporator to contain all of said liquid refrigerant draining from said first evaporator when said liquifying means is inoperative, said header being located out of heat exchange relation with said higher temperature enclosure and below said first evaporator to receive all of said draining liquid refrigerant.

2. A compartment type water cooler comprising an enclosure for the storage of ice cubes,

an enclosure for the storage of drinking water, and

a closed refrigerating circuit including: a compressor for supplying liquid refrigerant to said circuit,

a first evaporator disposed in heat transfer relation with said drinking water enclosure,

a second evaporator disposed in heat transfer relation with said ice cube storage compartment and in series refrigerant flow with said first evaporator,

restrictor means for controlling the flow of refrigerant to said second evaporator, and

means for draining liquid refrigerant from said first evaporator when said liquefying means is inoperative, said means including a header disposed between said first evaporator and said restrictor means, said header having sutficient volumetric capacity relative to said first evaporator to contain all of said liquid refrigerant draining from said first evaporator when said liquifying means is inoperative, said header being located out of heat exchange relation with said drinking water enclosure and below said first evaporator to receive all of said draining liquid refrigerant.

3. The water cooler as defined in claim 2 including control means for initiating and terminating the operation of said compressor in response to the temperature of said first evaporator.

4. A mechanically refrigerated cabinet having an enclosure to be maintained at a low temperature,

an enclosure to be maintained at a higher temperature,

and

a closed refrigerating circuit including: liquifying means for supplying liquid refrigerant to said circuit,

a first evaporator disposed in heat transfer relation with said higher temperature enclosure,

a second evaporator disposed in heat transfer relation with said low temperature enclosure and in series refrigerant flow with said first evaporator,

restrictor means for controlling the flow of refrigerant to said second evaporator, and

means for draining liquid refrigerant from said first evaporator when said liquefying means is inoperative, said means including an accumulator disposed between said first evaporator and said restrictor means,

said accumulator having inlet means disposed in spaced relation below said first evaporator, said accumulator further having sufficient volumetric capacity relative to said first evaporator to contain all of said liquid refrigerant draining from said first evaporator when said liquifying means is inoperative, said accumulator being located out of heat exchange relation With said higher temperature enclosure and below said first evaporator to receive all of said draining liquid refrigerant.

5. A compartment type water cooler comprising an enclosure for the storage of ice cubes,

an enclosure for the storage of drinking water, and

a closed refrigerating circuit including: a compressor for supplying liquid refrigerant to said circuit,

a first evaporator disposed in heat transfer relation with said drinking water enclosure,

a second evaporator disposed in heat transfer relation with said ice cube storage compartment and in series refrigerant flow with said first evaporator,

restrictor means for controlling the flow of refrigerant to said second evaporator, and

means for draining liquid refrigerant from said first evaporator When said liquefying means is inoperative, said means including a header disposed between said first evaporator and said restrictor means, said header further having sufficient volumetric capacity relative to said first evaporator to contain all of said liquid refrigerant draining from said first evaporator when said liquifying means is inoperative,

said header being located out of heat exchange relation with said drinking Water enclosure and below said first evaporator to receive all of said draining liquid refrigerant.

6. The water cooler as defined in claim 5 including control means for initiating and terminating the operation of said compressor in response to the temperature of said first evaporator.

References Cited by the Examiner UNITED STATES PATENTS 2,133,954 10/38 Buchanan 62-503 X 2,446,946 8/48 Mortar 62-503 X 2,605,621 8/52 Kellershon 62--394 X 2,712,732 7/55 McGrew 62526 X 2,758,446 8/56 Schumacher 62-526 X ROBERT A. OLEARY, Primary Examiner. 

1. A MECHANICALLY REFRIGERATED CABINET HAVING AN ENCLOSURE TO BE MAINTAINED AT A LOW TEMPERATURE AN ENCLOSURE TO BE MAINTAINED AT A HIGHER TEMPERATURE AND A CLOSED REFRIGERATING CIRCUIT INCLUDING: LIQUIFYING MEANS FOR SUPPLYING LIQUID REFRIGERANT TO SAID CIRCUIT, A FIRST EVAPORATOR DISPOSED IN HEAT TRANSFER RELATION WITH SAID HIGHER TEMPERATURE ENCLOSURE. A SECOND EVAPORATOR DISPOSED IN HEAT TRANSFER RELATION WITH SAID LOW TEMPERATURE ENCLOSURE AND IN SERIES REFRIGERANT FLOW WITH SAID FIRST EVAPORATOR RESTRICTOR MEANS FOR CONTROLLING THE FLOW OF REFRIGERANT TO SAID SECOND EVAPORATOR, AND MEANS FOR DRAINING LIQUID REFRIGERANT FROM SAID FIRST EVAPORTOR WHEN SAID LIQUEFYING MEANS IS INOPERATIVE, SAID MEANS INCLUDING A HEADER DISPOSED BETWEEN SAID FIRST EVAPORTOR AND SAID RECTRICTOR MEANS, SAID HEADER HAVING SUFFICIENT VOLUMETRIC CAPACITY RELATIVE TO SAID FIRST EVAPORATOR TO CONTAIN ALL OF SAID REFRIGERANT DRAINING FROM SAID FIRST EVAPORATOR WHEN SAID LIQUIFYING MEANS IS INOPERATIVE, SAID HEADER BEING LOCATED OUT OF HEAT EXCHANGER RELATION WITH SAID HIGHER TEMPERATURE ENCLOSURE AND BELOW SAID FIRST EVAPORATOR TO RECEIVE ALL OF SAID DRAINING LIQUID REFRIGERANT. 